(a) Field of the Invention
The present invention relates to a sound transmission system using the human body as a propagation medium, and more specifically, relates to a system for transmitting an audio signal through a human body by using two signal transmitters.
(b) Description of the Related Art
Human body communication is where a signal is transmitted by using a human body rather than by using a wire. In human body communication, the electric signal is transmitted through the human body without using electric wires since the human body conducts electricity.
In a conventional sound transmission system using the human body as a communication channel, an audio signal is delivered when both a transmitter transmitting a modulated electric signal and a receiver receiving the transmitted electric signal and demodulating the received electric signal to an audio signal of sensible frequency bandwidth are directly attached to the human body. That is, in the conventional sound transmission system, when the audio signal to be delivered is modulated to an electric signal transmittable through the human body and the modulated electric signal is output to be transmitted through the human body, the receiver attached to an area around an ear of the human body receives the transmitted electric signal and demodulates the signal to convert it to an audible sound. However, there are inconveniences in that it is required to provide the transmitter and the receiver respectively for the conventional sound transmission system and the sound may be heard only if the receiver is attached to the human body.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a user of ordinary skill in the art.